GCP Firewall Rule Deletion

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Identifies when a firewall rule is deleted in Google Cloud Platform (GCP). Virtual Private Cloud (VPC) firewall rules can be configured to allow or deny connections to or from virtual machine (VM) instances. An adversary may delete a firewall rule in order to weaken their target’s security controls.

Rule type: query

Rule indices:

  • filebeat-*
  • logs-gcp*

Severity: medium

Risk score: 47

Runs every: 5 minutes

Searches indices from: now-6m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

Tags:

  • Elastic
  • Cloud
  • GCP
  • Continuous Monitoring
  • SecOps
  • Configuration Audit

Version: 5 (version history)

Added (Elastic Stack release): 7.10.0

Last modified (Elastic Stack release): 7.13.0

Rule authors: Elastic

Rule license: Elastic License v2

Potential false positives

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Firewall rules may be deleted by system administrators. Verify that the firewall configuration change was expected. Exceptions can be added to this rule to filter expected behavior.

Investigation guide

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Config

The GCP Fleet integration, Filebeat module, or similarly structured data is required to be compatible with this rule.

Rule query

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event.dataset:(googlecloud.audit or gcp.audit) and
event.action:v*.compute.firewalls.delete

Threat mapping

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Framework: MITRE ATT&CKTM

Rule version history

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Version 5 (7.13.0 release)
  • Formatting only
Version 4 (7.12.0 release)
  • Formatting only
Version 3 (7.11.2 release)
  • Formatting only
Version 2 (7.11.0 release)
  • Updated query, changed from:

    event.dataset:googlecloud.audit and
    event.action:v*.compute.firewalls.delete